The plural of anecdote is not data, as scientists will tell you, but consider these snapshots of the emerging happiness debate anyway: Lately, Jerome Wakefield's students have been coming up to him after they break up with a boyfriend or girlfriend, and not because they want him to recommend a therapist. Wakefield, a professor at New York University, coauthored the 2007 book The Loss of Sadness: How Psychiatry Transformed Normal Sorrow Into Depressive Disorder, which argues that feeling down after your heart is broken - even so down that you meet the criteria for clinical depression - is normal and even salutary. But students tell him that their parents are pressuring them to seek counseling and other medical intervention - "some Zoloft, dear?" - for their sadness, and the kids want no part of it. "Can you talk to them for me?" they ask Wakefield. Rather than "listening to Prozac," they want to listen to their hearts, not have them chemically silenced.

University of Illinois psychologist Ed Diener, who has studied happiness for a quarter century, was in Scotland recently, explaining to members of Parliament and business leaders the value of augmenting traditional measures of a country's wealth with a national index of happiness. Such an index would measure policies known to increase people's sense of well-being, such as democratic freedoms, access to health care and the rule of law. The Scots were all in favor of such things, but not because they make people happier. "They said too much happiness might not be such a good thing," says Diener. "They like being dour, and didn't appreciate being told they should be happier." (For one man's struggle with the pressure to pursue happiness, click here.)

Eric Wilson tried to get with the program. Urged on by friends, he bought books on how to become happier. He made every effort to smooth out his habitual scowl and wear a sunny smile, since a happy expression can lead to genuinely happy feelings. Wilson, a professor of English at Wake Forest University, took up jogging, reputed to boost the brain's supply of joyful neurochemicals, watched uplifting Frank Capra and Doris Day flicks and began sprinkling his conversations with "great!" and "wonderful!", the better to exercise his capacity for enthusiasm. When none of these made him happy, Wilson not only jumped off the happiness bandwagon - he also embraced his melancholy side and decided to blast a happiness movement that "leads to half-lives, to bland existences," as he argues in Against Happiness, a book now reaching stores. Americans' fixation on happiness, he writes, fosters "a craven disregard for the value of sadness" and "its integral place in the great rhythm of the cosmos."

It's always tricky to identify a turning point, at least in real time. Only in retrospect can you accurately pinpoint when a financial market peaked or hit bottom, for instance, or the moment when the craze for pricey coffee drinks crested. But look carefully, and what you are seeing now may be the end of the drive for ever-greater heights of happiness. Fed by hundreds of self-help books, including the current The How of Happiness: A Scientific Approach to Getting the Life You Want, magazine articles and an industry of life coaches and motivational speakers, the happiness movement took off in the 1990s with two legitimate developments: discoveries about the brain activity underlying well-being, and the emergence of "positive psychology," whose proponents urged fellow researchers to study happiness as seriously as they did pathological states such as depression. But when the science of happiness collided with pop culture and the marketplace, it morphed into something even its creators hardly recognized. There emerged "a crowd of people out there who want you to be happier," write Ed Diener and his son, Robert Biswas-Diener, in their book, Rethinking Happiness, due for publication later this year. Somewhere out there a pharmaceutical company "is working on a new drug to make you happier," they warn. "There are even people who would like to give you special ozone enemas to make you happier." Although some 85 percent of Americans say they're pretty happy, the happiness industry sends the insistent message that moderate levels of well-being aren't enough: not only can we all be happier, but we practically have a duty to be so. What was once considered normal sadness is something to be smothered, even shunned.

The backlash against the happiness rat race comes just when scientists are releasing the most-extensive-ever study comparing moderate and extreme levels of happiness, and finding that being happier is not always better. In surveys of 118,519 people from 96 countries, scientists examined how various levels of subjective well-being matched up with income, education, political participation, volunteer activities and close relationships. They also analyzed how different levels of happiness, as reported by college students, correlated with various outcomes. Even allowing for imprecision in people's self-reported sense of well-being, the results were unambiguous. The highest levels of happiness go along with the most stable, longest and most contented relationships. That is, even a little discontent with your partner can nudge you to look around for someone better, until you are at best a serial monogamist and at worst never in a loving, stable relationship. "But if you have positive illusions about your partner, which goes along with the highest levels of happiness, you're more likely to commit to an intimate relationship," says Diener.

In contrast, "once a moderate level of happiness is achieved, further increases can sometimes be detrimental" to income, career success, education and political participation, Diener and colleagues write in the journal Perspectives on Psychological Science. On a scale from 1 to 10, where 10 is extremely happy, 8s were more successful than 9s and 10s, getting more education and earning more. That probably reflects the fact that people who are somewhat discontent, but not so depressed as to be paralyzed, are more motivated to improve both their own lot (thus driving themselves to acquire more education and seek ever-more-challenging jobs) and the lot of their community (causing them to participate more in civic and political life). In contrast, people at the top of the jolliness charts feel no such urgency. "If you're totally satisfied with your life and with how things are going in the world," says Diener, "you don't feel very motivated to work for change. Be wary when people tell you you should be happier."

The drawbacks of constant, extreme happiness should not be surprising, since negative emotions evolved for a reason. Fear tips us off to the presence of danger, for instance. Sadness, too, seems to be part of our biological inheritance: apes, dogs and elephants all display something that looks like sadness, perhaps because it signals to others a need for help. One hint that too much euphoria can be detrimental comes from studies finding that among people with late-stage illnesses, those with the greatest sense of well-being were more likely to die in any given period of time than the mildly content were. Being "up" all the time can cause you to play down very real threats.

Eric Wilson needs no convincing that sadness has a purpose. In his Against Happiness, he trots out criticisms of the mindless pursuit of contentment that philosophers and artists have raised throughout history - including that, as Flaubert said, to be chronically happy one must also be stupid. Less snarkily, Wilson argues that only by experiencing sadness can we experience the fullness of the human condition. While careful not to extol depression - which is marked not only by chronic sadness but also by apathy, lethargy and an increased risk of suicide - he praises melancholia for generating "a turbulence of heart that results in an active questioning of the status quo, a perpetual longing to create new ways of being and seeing." This is not romantic claptrap. Studies show that when you are in a negative mood, says Diener, "you become more analytical, more critical and more innovative. You need negative emotions, including sadness, to direct your thinking." Abraham Lincoln was not hobbled by his dark moods bordering on depression, and Beethoven composed his later works in a melancholic funk. Vincent van Gogh, Emily Dickinson and other artistic geniuses saw the world through a glass darkly. The creator of Peanuts, Charles M. Schulz, was known for his gloom, while Woody Allen plumbs existential melancholia for his films, and Patti Smith and Fiona Apple do so for their music.

Wilson, who asserts that "the happy man is a hollow man," is hardly the first scholar to see melancholia as muse. A classical Greek text, possibly written by Aristotle, asks, "Why is it that all those who have become eminent in philosophy or politics or poetry or the arts are clearly melancholic?" Wilson's answer is that "the blues can be a catalyst for a special kind of genius, a genius for exploring dark boundaries between opposites." The ever-restless, the chronically discontent, are dissatisfied with the status quo, be it in art or literature or politics.

For all their familiarity, these arguments are nevertheless being crushed by the happiness movement. Last August, the novelist Mary Gordon lamented to The New York Times that "among writers ... what is absolutely not allowable is sadness. People will do anything rather than to acknowledge that they are sad." And in a My Turn column in Newsweek last May, Jess Decourcy Hinds, an English teacher, recounted how, after her father died, friends pressed her to distract herself from her profound sadness and sense of loss. "Why don't people accept that after a parent's death, there will be years of grief?" she wrote. "Everyone wants mourners to 'snap out of it' because observing another's anguish isn't easy."

It's hard to say exactly when ordinary Americans, no less than psychiatrists, began insisting that sadness is pathological. But by the end of the millennium that attitude was well entrenched. In 1999, Arthur Miller's Death of a Salesman was revived on Broadway 50 years after its premiere. A reporter asked two psychiatrists to read the script. Their diagnosis: Willy Loman was suffering from clinical depression, a pathological condition that could and should be treated with drugs. Miller was appalled. "Loman is not a depressive," he told The New York Times. "He is weighed down by life. There are social reasons for why he is where he is." What society once viewed as an appropriate reaction to failed hopes and dashed dreams, it now regards as a psychiatric illness.

That may be the most damaging legacy of the happiness industry: the message that all sadness is a disease. As NYU's Wakefield and Allan Horwitz of Rutgers University point out in The Loss of Sadness, this message has its roots in the bible of mental illness, the Diagnostic and Statistical Manual of Mental Disorders. Its definition of a "major depressive episode" is remarkably broad. You must experience five not-uncommon symptoms, such as insomnia, difficulty concentrating and feeling sad or empty, for two weeks; the symptoms must cause distress or impairment, and they cannot be due to the death of a loved one. Anyone meeting these criteria is supposed to be treated.

Yet by these criteria, any number of reactions to devastating events qualify as pathological. Such as? For three weeks a woman feels sad and empty, unable to generate any interest in her job or usual activities, after her lover of five years breaks off their relationship; she has little appetite, lies awake at night and cannot concentrate during the day. Or a man's only daughter is suffering from a potentially fatal blood disorder; for weeks he is consumed by despair, cannot sleep or concentrate, feels tired and uninterested in his usual activities.

Horwitz and Wakefield do not contend that the spurned lover or the tormented father should be left to suffer. Both deserve, and would likely benefit from, empathic counseling. But their symptoms "are neither abnormal nor inappropriate in light of their" situations, the authors write. The DSM definition of depression "mistakenly encompasses some normal emotional reactions," due to its failure to take into account the context or trigger for sadness.

That has consequences. When someone is appropriately sad, friends and colleagues offer support and sympathy. But by labeling appropriate sadness pathological, "we have attached a stigma to being sad," says Wakefield, "with the result that depression tends to elicit hostility and rejection" with an undercurrent of " 'Get over it; take a pill.' The normal range of human emotion is not being tolerated." And insisting that sadness requires treatment may interfere with the natural healing process. "We don't know how drugs react with normal sadness and its functions, such as reconstituting your life out of the pain," says Wakefield.

Even the psychiatrist who oversaw the current DSM expresses doubts about the medicalizing of sadness. "To be human means to naturally react with feelings of sadness to negative events in one's life," writes Robert Spitzer of the New York State Psychiatric Institute in a foreword to The Loss of Sadness. That would be unremarkable if it didn't run completely counter to the message of the happiness brigades. It would be foolish to underestimate the power and tenacity of the happiness cheerleaders. But maybe, just maybe, the single-minded pursuit of happiness as an end in itself, rather than as a consequence of a meaningful life, has finally run its course.